<meta charset="utf-8">
(#) `android:alpha` attribute missing on `ColorStateList`

!!! ERROR: `android:alpha` attribute missing on `ColorStateList`
   This is an error.

Id
:   `UseAndroidAlpha`
Summary
:   `android:alpha` attribute missing on `ColorStateList`
Severity
:   Error
Category
:   Correctness
Platform
:   Android
Vendor
:   Android Open Source Project
Identifier
:   androidx.appcompat
Feedback
:   https://issuetracker.google.com/issues/new?component=460343
Min
:   Lint 7.0
Compiled
:   Lint 8.0 and 8.1
Artifact
:   [androidx.appcompat:appcompat](androidx_appcompat_appcompat.md.html)
Since
:   1.2.0
Affects
:   Resource files
Editing
:   This check runs on the fly in the IDE editor
Implementation
:   [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/appcompat/appcompat-lint/src/main/kotlin/androidx/appcompat/res/ColorStateListAlphaDetector.kt)
Tests
:   [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/appcompat/appcompat-lint/src/test/kotlin/androidx/appcompat/lint/res/ColorStateListAlphaDetectorTest.kt)
Copyright Year
:   2019

`ColorStateList` uses app:alpha without `android:alpha`

!!! Tip
   This lint check has an associated quickfix available in the IDE.

(##) Including

!!!
   This is not a built-in check. To include it, add the below dependency
   to your project.

```
// build.gradle.kts
implementation("androidx.appcompat:appcompat:1.7.0")

// build.gradle
implementation 'androidx.appcompat:appcompat:1.7.0'

// build.gradle.kts with version catalogs:
implementation(libs.appcompat)

# libs.versions.toml
[versions]
appcompat = "1.7.0"
[libraries]
# For clarity and text wrapping purposes the following declaration is
# shown split up across lines, but in TOML it needs to be on a single
# line (see https://github.com/toml-lang/toml/issues/516) so adjust
# when pasting into libs.versions.toml:
appcompat = {
    module = "androidx.appcompat:appcompat",
    version.ref = "appcompat"
}
```

1.7.0 is the version this documentation was generated from;
there may be newer versions available.

[Additional details about androidx.appcompat:appcompat](androidx_appcompat_appcompat.md.html).
(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Adding the suppression attribute `tools:ignore="UseAndroidAlpha"` on
  the problematic XML element (or one of its enclosing elements). You
  may also need to add the following namespace declaration on the root
  element in the XML file if it's not already there:
  `xmlns:tools="http://schemas.android.com/tools"`.

  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;selector xmlns:tools="http://schemas.android.com/tools"
      tools:ignore="UseAndroidAlpha" ...&gt;
    ...
  &lt;/selector&gt;
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="UseAndroidAlpha" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'UseAndroidAlpha'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore UseAndroidAlpha ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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